A Hydroponic Fertilizer Formulation for Cannabis Using Peters 20-10-20

The following is a simple fertilization formula for growing cannabis in hydroculture using Peters Professional 20-10-20 ‘Peat-Lite Special’ water soluble fertilizer. This formulation has been trialed successfully in my gardens in Fafard Peat-Lite growing media.

This formula can be run throughout the life cycle of the crop, from the seedling stage to finish. However, I have found that a switch to the Peters 10-30-20 fertilizer from flower induction to harvest produces a heavier and more desirable flower. I hope you find this information useful.

Materials needed:

Peters Professional 20-10-20 “Peat-Lite Special” water soluble fertilizer – sold in 25 lbs. bag

Magnesium Sulphate (Epsom Salts) – sold in 50 lbs. bag

To make a single tank concentrate to be injected into a water line at 1:100 mix the following:

190.73g Peters Professional 20-10-20 “Peat-Lite Special” water soluble fertilizer

92.00g Magnesium Sulphate (Epsom Salts)

water to make 1 gallon

Inject this concentrate at 1:100 to deliver PPM 100-22-84-00-25 (N-P-K-Ca-Mg). This will make exactly 100 gallons of working solution.

To make a working solution to be top fed, dripped or used in flood tables mix the following:

1.90g/gallon Peters Professional 20-10-20 “Peat-Lite Special” water soluble fertilizer

0.92g/gallon Magnesium Sulphate (Epsom Salts)

Mixed together this will deliver PPM 100-22-84-00-25 (N-P-K-Ca-Mg).

*Note: this formulation does not provide a calcium component. Calcium is provided as lime in the Peat-Lite media I use. I recommend Fafard Urban Mix A or Fafard Organic Formula FOF-30. These mixes are both limed at a rate of 3lbs/yard.

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3 Responses to A Hydroponic Fertilizer Formulation for Cannabis Using Peters 20-10-20

  1. […] veg these using the Peters 20-10-20 formulation, then switch to the Peters 10-30-20 formulation when it’s time to induce flowering. It will […]

  2. […] These are being fed the Peters 20-10-20 @ 100 PPM Nitrogen. The formulation can be found in this post. […]

  3. […] These are being transplanted into #10 nursery containers (10 gallon) filled with Fafard Urban Mix ‘A’. The Fafard mixes come in 79.3L bags, which is just shy of 21 gallons. This means I can generously fill two #10 containers with one bag of mix. They’ll be watered in using the Peters 20-10-20 @ 100 PPM nitrogen. […]

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